U.S. patent number 5,412,375 [Application Number 08/127,216] was granted by the patent office on 1995-05-02 for method of selecting an air interface for communication in a communication system.
This patent grant is currently assigned to Motorola, Inc.. Invention is credited to Daniel E. Wood.
United States Patent |
5,412,375 |
Wood |
May 2, 1995 |
Method of selecting an air interface for communication in a
communication system
Abstract
In a communication system having a plurality of air interfaces,
one of the air interfaces is assigned for use for a desired
communication by transmitting a message, having a list of air
interface capabilities of the subscriber, from the subscriber to a
base (12). A list of air interface capabilities of the base is then
compared, at a controller, with the list from the subscriber (14).
A compatible air interface, or list of compatible air interfaces,
is generated by the controller and provided to the base (15, 31).
The base will then direct the subscriber to access the
communication system utilizing a compatible air interface (18,
35).
Inventors: |
Wood; Daniel E. (Crystal Lake,
IL) |
Assignee: |
Motorola, Inc. (Schaumburg,
IL)
|
Family
ID: |
22428919 |
Appl.
No.: |
08/127,216 |
Filed: |
September 27, 1993 |
Current U.S.
Class: |
455/451 |
Current CPC
Class: |
H04W
48/18 (20130101); H04W 8/22 (20130101); H04W
72/042 (20130101) |
Current International
Class: |
H04Q
7/38 (20060101); H01H 067/00 () |
Field of
Search: |
;340/825.03 ;375/5
;455/33.1,33.2,54.1 ;379/59,60 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Yusko; Donald J.
Assistant Examiner: Miller; Gregg V.
Attorney, Agent or Firm: Warren; Raymond J.
Claims
The invention claimed is:
1. A method, for use in a communication system having a plurality
of air interfaces, of assigning one of said plurality of air
interfaces to a subscriber, said method comprising the steps
of:
transmitting a message from said subscriber to a base of said
communication system, said message having a list of air interface
capabilities of said subscriber;
transmitting said list of air interface capabilities and a list of
air interface capabilities of said base to a controller of said
communication system;
selecting, at said controller, an air interface based upon a
comparison of said lists of air interface capabilities of said
subscriber and said base;
informing said base of said air interface selected by said
controller; and
directing said subscriber to utilize said air interface selected by
said controller.
2. The method of claim 1 wherein said step of selecting said air
interface further comprises the step of making said selection based
upon a feature capability of said subscriber.
3. The method of claim 1 further comprising the steps of:
accepting, at said base, said air interface selected by said
controller;
notifying said controller if said base rejects said air interface
selected by said controller;
selecting a new air interface based upon said comparison of said
lists of air interface capabilities of said subscriber and said
base if said new air interface exists;
advising said base that said new air interface has been selected if
said new air interface exists; and
advising said base of the lack of a new air interface if said new
air interface is not selected.
4. The method of claim 1 wherein said plurality of air interfaces
comprises an analog air interface and a digital air interface.
5. The method of claim 4 wherein said digital air interface is a
time division multiple access system or a code division multiple
access system.
6. The method of claim 1 further comprising the step of selecting
an air interface, at said base, if said controller fails to inform
said base of said air interface selected being selected.
7. A method, for use in a communication system having a plurality
of air interfaces, of assigning one of said plurality of air
interfaces to a subscriber, said method comprising the step of:
transmitting a message from said subscriber to a base of said
communication system, said message having a list of air interface
capabilities of said subscriber;
transmitting said list of said air interface capabilities of said
subscriber and a list of air interface capabilities of said base to
a controller;
selecting, at said controller, a first air interface based upon a
comparison of said lists of air interface capabilities of said
subscriber and said base;
informing said base of said first air interface;
directing said subscriber to utilize said first air interface if
said base accepts said first air interface;
notifying said controller if said base rejects said first air
interface;
selecting, at said controller, a second air interface, if said
second air interface exists, based upon said comparison of said
lists of air interface capabilities of said subscriber and
base;
informing said base of said second air interface; and
directing said subscriber to utilize said second air interface if
said base accepts said second air interface.
8. The method of claim 7 wherein said plurality of air interfaces
comprises an analog air interface and a digital air interface.
9. The method of claim 8 wherein said digital air interface is a
time division multiple access system or a code division multiple
access system.
10. The method of claim 7 further comprising the step of selecting
an air interface, at said base, if said controller fails to inform
said base of said air interface selected.
11. A method, for use in a communication system having a plurality
of air interfaces, of assigning one of said plurality of air
interfaces to a subscriber, said method comprising the step of:
transmitting a message from said subscriber to a base of said
communication system, said message having a list of air interface
capabilities of said subscriber;
transmitting said list of air interface capabilities of said
subscriber and a list of air interface capabilities of said base to
a controller of said communication system;
creating, at said controller, a compatible air interface list based
upon a comparison of said lists of air interface capabilities of
said subscriber and said base;
informing said base of said compatible air interface list;
directing said subscriber to utilize a first compatible air
interface from said compatible air interface list if at least one
compatible air interface is available;
directing said subscriber to utilize said first compatible air
interface if said first compatible air interface is available;
and
denying access to said subscriber if said first compatible air
interface is unavailable.
12. The method of claim 11 wherein said plurality of air interfaces
comprises an analog air interface and a digital air interface.
13. The method of claim 12 wherein said digital air interface is a
time division multiple access system or a code division multiple
access system.
14. The method of claim 11 further comprising the step of selecting
an air interface, at said base, if said controller fails to inform
said base of said air interface selected.
Description
FIELD OF THE INVENTION
The present invention relates, in general, to communication systems
and, more particularly, to a method of selecting an air interface
for communication in a communication system.
BACKGROUND OF THE INVENTION
Presently, communication systems, particularly cellular
communication systems, operate on one basic air interface standard.
For example there are Analog Mobile Phone Systems (AMPS) whose air
interface is described in detail in EIA/TIA (Electronics Industry
Association/Telecommunications Industry Association) IS-53 (Interim
Standard). Other standards include the presently pending TDMA (Time
Division Multiple Access) standard, IS-54, and a CDMA (Code
Division Multiple Access) standard, IS-95.
In order to provide compatible systems, subscriber units are being
provided which will operate on both, or multiple, systems. These
are commonly referred to as dual mode, or multimode, subscriber
units. However, in places where newer systems, (TDMA or) CDMA, are
available along with an AMPS system, there may be a separate
network providing service to the subscriber. In operation, the dual
mode subscriber would first attempt to access the CDMA system.
Failing this, the dual mode subscriber would attempt to access the
AMPS system.
In the future, it is envisioned that the networks will also be
dual, or multiple, mode by offering more than one air interface
type over which to operate. When this occurs, it will be necessary
for the network to determine what type of several air interfaces to
which a subscriber, having multiple modes, will be assigned.
Therefore, there is a need to provide a method of matching and
selecting the appropriate air interface to be used for the
communication.
SUMMARY OF THE INVENTION
The present invention provides a method of selecting an air
interface with takes into account the capabilities of the
subscriber and the particular system side transceiver with which it
desires to communicate. More particularly, in a communication
system having a plurality of air interfaces, one of the air
interfaces is assigned for use for a desired communication by
transmitting a message, having a list of air interface capabilities
of the subscriber, from the subscriber to a base. A list of air
interface capabilities of the base is then compared, at a
controller, with the list from the subscriber. A compatible air
interface, or list of compatible air interfaces, is generated by
the controller and provided to the base. The base will then direct
the subscriber to access the communication system utilizing a
compatible air interface.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a block diagram of a system flow chart illustrating one
embodiment of the present invention;
FIG. 2 is a block diagram of a system flow chart illustrating a
second embodiment of the present invention;
FIG. 3 is a block diagram of a flow chart illustrating a third
embodiment of the present invention; and
FIG. 4 is a block diagram representing a communication system
capable of utilizing the present invention.
DETAILED DESCRIPTION OF THE DRAWINGS
Referring initially to FIG. 1, a flow chart of a process, generally
designated 10, of one embodiment of the present invention is
illustrated. Process 10 begins at step 11 when a call setup is
requested. This request may be generated by a subscriber unit, such
as units 41 and 42 of FIG. 4; or may be requested by the network,
such as network 43.
Once a call setup has been requested, subscriber 41 will transmit a
message to a base 44. This message will contain a list of the air
interface capabilities of subscriber 41, step 11. In this example,
subscriber 41 will show that it is compatible with air interfaces
#1 and #3. An example of the type of messaging used in
communication systems can be found in the GSM (Groupe Special
Mobile also known as the Global System for Mobile communication)
TDMA standard. In particular GSM Recommendation 08.08, v3.10.1,
.sctn.3.2.1 (2/92), illustrates current message assignments.
Once the message from the subscriber is received, base 44 transmits
this information along with its own air interface capabilities to a
controller 45, step 13. It should be noted here that the controller
may be a part of a base site 43, represented by the dashed line of
FIG. 4, or may be separate from the base site. One type of separate
controller is a Mobile Switching Center (MSC), which serves as the
connection with the Public Switched Telephone Network (PSTN) 46. In
this example, the air interface capabilities of the base are air
interfaces #1, #2, #3, and #N.
Controller 45 will select an air interface to be used based upon a
comparison of the lists from the subscriber and the base, step 14.
Base 44 is then informed of the selection, step 15. Process 10 next
enters a subprocess 16 where the controller and base interact to
complete the air interface assignment process. The next step in
process 10 is a decision step 17 where it is determined if the base
will accept the selection made by controller 45. This step is
necessary since it is possible that the resources needed to
function with the selected air interface may not be available. For
instance, when the setup process begins, steps 12 and 13, base 44
has air interface #1 available. However, before the selection is
made by controller 45, the resources for air interface #1 may have
been assigned by base 44 to another call. Therefore, base 44 would
not be able to accept the air interface selection of controller
45.
If base 44 does accept the selection from controller 45, a message
is sent to subscriber 41 indicating the air interface selected,
step 18, and the call connection is completed, step 19.
If base 44 does not accept the selection from controller 45, then
base 44 will notify the controller of the rejection, step 20. Upon
notification, controller 45 will determine if more compatible air
interfaces are available, decision step 21. If there are no more
compatible air interfaces, base 44 is notified, step 23, and the
call attempt will fail, step 24. If there are other compatible air
interfaces available, another selection will be made by controller
45, step 22, and the base will be notified, step 15. Subprocess 16
will repeat until a solution is reached.
In the present example, both the subscriber and base will operate
on air interface #3. Therefore, air interface #3 would be selected
in step 22 and conveyed to the base, step 15. If this is rejected
by the base, since there are no other compatible air interfaces
available, the access would fail, step 24.
It is also possible in the above selection process by controller 45
to consider authorized features available to the subscriber. This
would be used in step 14. For example, for political reasons (e.g.
if dual mode phones are required) or business reasons (e.g. a dual
mode phone costs the same to make as a single mode phone) a
subscriber may have a dual mode phone, but not be authorized to use
both modes. One situation where a feature would have an impact on
an air interface selection is where different rates are charged for
different air interfaces. Given that air interface #3 is a higher
quality interface, the subscriber would be charged more for access
to that air interface. However, if air interface #3 is at capacity,
the subscriber would generally rather get the lower quality air
interface #1 than be denied a call. In this case, the process would
proceed as described above with the controller first selecting air
interface #3 and then #1, if #3 was rejected by the base.
On the other hand, a user may elect to only subscribe to the less
expensive, lower quality air interface #1, even though the
subscriber unit could operate on both air interfaces. In this
instance, a limitation against assignment to air interface #3 would
be stored in a subscriber feature file in the system. When the
controller went to select the air interface, air interface #3 would
be eliminated based upon the subscriber features listed as being
available.
Referring now to FIG. 2, a flow chart of a process, generally
designated 30, of a second embodiment of the present invention is
illustrated. Process 30 begins in the same manner as process 10 by
obtaining a list of air interface capabilities of the subscriber
and base and forwarding these lists to controller 45, steps 11-14.
In this embodiment, instead of selecting one air interface and
notifying the base, controller 45 provides a list of compatible air
interfaces to base 44, step 31. The base then takes the actions set
forth in subprocess 32.
Once the list of compatible air interfaces is received by base 44,
it determines if at least one of the listed air interfaces is
available. If not available, the access attempt fails, step 24. If
there is at least one compatible air interface, base 44 will assign
the call to one of the compatible air interfaces, step 35. The
connection will then be completed, step 19.
In this embodiment, the list generated may have some intelligence
associated therewith. For example, the compatible list may be rank
ordered by some operator designated preference. In addition, the
list may be modified by particular subscriber features as described
above. Namely, air interface #3 may be ranked preferable to air
interface #1; or air interface #1 may not be subscribed to by the
user and, therefore would not be included on the list.
Referring now to FIG. 3, a flow chart of a process, generally
designated 50, of a third embodiment of the present invention is
illustrated. Process 50 represents the actions taken from more of a
base perspective. Process 50 begins in the same manner as processes
10 and 30 by obtaining and conveying the lists air interface lists,
steps 11-13. However the base should not be designed to await an
indefinite amount of time for a response. Instead, the base will
set a response timer, step 51.
If a reply is received from controller 45 before the response timer
expires, step 52, then process 50 will proceed with subprocess 53.
Subprocess 53 can be either subprocess 16 of FIG. 1 or subprocess
32 of FIG. 2.
If a reply is not received from controller 45 within the response
time, process 50 proceeds to decision step 54 where base 44
determines if there is a compatible air interface between itself
and the subscriber. If no compatible air interface exists, then the
access fails, step 24. If there is one or more compatible air
interfaces, then the base selects one, step 56, and the connection
is completed, step 19.
A benefit of this type of architecture is that multiple air
interface standards can be provided for at a single location. This
eliminates the need to install separate equipment for each air
interface and allows for dynamic allocation of compatible resources
at the base sites. It also gives the system operators the ability
to shift systems gradually from one air interface to another
without having to install separate systems.
Thus, it will be apparent to one skilled in the art that there has
been provided in accordance with the invention, a method of
selecting an air interface for communication in a communication
system that fully satisfies the objects, aims, and advantages set
forth above.
While the invention has been described in conjunction with specific
embodiments thereof, it is evident that many alterations,
modifications, and variations will be apparent to those skilled in
the art in light of the foregoing description. Accordingly, it is
intended to embrace all such alterations, modifications, and
variations in the appended claims.
* * * * *